with the initial condition \( y(0)=2\)  [1]}. \(F(r)\)  and \(Q(r)\)  are functionals of \({\cal E}(r)\) , \(P(r)\)  and \(M(r)\)  defined as [2]}, [1]}
\(F(r)=\left[ 1- \frac{4\pi r^2 G}{c^4}\left({\cal E} (r)-P(r) \right)\right]\left(1-\frac{2M(r)G}{rc^2} \right)^{-1},\) 
